Next-day air. Delivery in thirty minutes or less. The information superhighway. Our society demands speed, convenience, and efficiency in the delivery of products and services. The communications industry is not exempt from these demands. To be competitive, a provider of communications network services must provide customers with service in a quick, convenient, and efficient manner, and as inexpensively as possible. To remain competitive, such a service provider also must provide customers with new services in a quick, convenient, and efficient manner, and as inexpensively as possible.
Recent advances and improvements in communications technology, such as fiber optic cables and optical networks, provide the communications industry with enormous opportunities to improve existing services and to branch into new services. Thousands of miles of fiber optic cable have been deployed in optical networks. These optical networks make possible the transmission of large amounts of information at great speeds. Optical networks have been used primarily to carry voice signals in telecommunication applications. However, the advanced features of optical networks allow for the transmission of other information such as data, video and multimedia signals. Thus, the communications industry is ideally suited to provide advanced services including the transmission of data, video and multimedia signals.
For example, optical networks may be used to carry the information that provides a subscriber with home entertainment services. Ideally, the subscriber places an order for home delivery of some entertainment such as some music, a video or a movie through the use of a telephone (or other customer premises equipment). The music, video or movie is almost instantaneously delivered over a networked communications system to the subscriber's home entertainment center. The information regarding both order placement and order delivery is carried, at least in part, over optical networks. Thus, the advanced features of optical networks as information transport facilities allow for the provision of new and improved services to subscribers, such as home entertainment services. The advanced features of optical networks provide other opportunities as well. Such opportunities include videoconferencing services, customized services for the provision of special news, sports or entertainment programming as well as other services.
As noted, optical networks provide opportunities for the delivery of new and improved services. However, the cost of these new and improved services to subscribers remains high. The high cost stands as an impediment to the promulgation and acceptance of the new and improved services. One reason for the high cost is an inefficiency in the transport of certain types of information through optical networks. The inefficiency is discussed in further detail below in connection with a brief description of information transport facilities including optical networks.
To deliver information from one point to another, and especially to deliver data, video or multimedia signals from one point to another, service providers have used information transport facilities that include a combination of an asynchronous transfer mode (ATM) system and one or more optical networks. There are drawbacks to the use of this combination as an information transport facility. One drawback is that the transfer of information in an ATM system and an optical network often results in inefficiencies in the transport of the information in the optical network. In other words, an ATM system often transfers information to an optical network in an amount that is much less than the maximum capacity that can be handled by the optical network. This inefficient transfer of information fails to take advantage of the advanced information transmission capabilities of optical networks. This inefficient transfer of information also may actually slow the transmission of information because the inefficient transfers of information take up bandwidth capacity and use up time that could be allocated to more efficient transfers of information.
In addition, the inefficiencies in transport of information through optical networks serve to maintain (rather than to reduce) the generally high cost of use of these networks. By way of explanation, the cost of use of an optical network is approximately the same whatever amount of information is being carried within the bandwidth capacity of the optical network. Inefficient use of the optical network does not allow for much distribution of the cost of use over the different blocks of information transmitted and/or those parties using the optical network. Efficient use of the optical network allows for a greater distribution of the cost of use over the blocks of information transmitted and/or those parties using the optical network. A lower cost for use of the optical network may be achieved by providing that the optical network carries the maximum amount of information and by distributing the cost of the use of the optical network over the maximum amount of information.
To explain the inefficiencies in the transfer of information between an ATM system and an optical network, a basic description of an information transport facility that includes an ATM system and an optical network is provided below.